The reference OMIM entry for this protein is 607386

Intraflagellar transport 172, chlamydomonas, homolog of; ift172
Selective lim-binding factor, rat, homolog of; slb
Kiaa1179

CLONING

By sequencing clones obtained from a size-fractionated brain cDNA library, Hirosawa et al. (1999) cloned SLB, which they designated KIAA1179. The deduced protein contains 1,090 amino acids and shares significant homology with the kinesin light chain repeat (see 600025) sequence. RT-PCR analysis revealed highest expression of SLB in testis and lowest expression in spleen. All other tissues and brain regions tested showed low-to-moderate expression. Howard and Maurer (2000) cloned Slb from a rat pituitary cell cDNA library. The 1,749-amino acid protein contains 7 N-terminal WD40 repeats and a nuclear localization signal. Highest expression was found in rat testis and pituitary cells.

MAPPING

By radiation hybrid analysis, Hirosawa et al. (1999) mapped the SLB gene to chromosome 2. Gross (2014) mapped the IFT172 gene to chromosome 2p23.3 based on an alignment of the IFT172 sequence (GenBank GENBANK BC137126) with the genomic sequence (GRCh37).

GENE FUNCTION

Howard and Maurer (2000) determined that rat Slb specifically binds to Lhx3 (600577) and Lhx4 (602146) with high affinity both in vitro and in vivo. Expression of the LIM-interacting domain of Slb reduced the expression of an Lhx3-responsive reporter gene.

MOLECULAR GENETICS

- Short-Rib Thoracic Dysplasia With or Without Polydactyly 10 In 14 patients from 12 families with short-rib thoracic dysplasia with or without polydactyly (SRTD10; 615630), Halbritter et al. (2013) identified homozygous or compound heterozygous mutations in the IFT172 gene (see, e.g., 607386.0001-607386.0012). Fibroblasts from affected individuals showed disturbed ciliary composition, suggesting alteration of ciliary transport and signaling, and knockdown of ift172 in zebrafish recapitulated the human phenotype. - Retinitis Pigmentosa 71 In 4 patients with retinitis pigmentosa-71 (RP71; 616394) from 3 unrelated families, Bujakowska et al. (2015) identified homozygosity or compound heterozygosity for mutations in the IFT172 gene (607386.0013-607386.0017) that segregated with disease in the respective families.

ANIMAL MODEL

In a screen for embryonic patterning mutations induced by ethylnitrosourea, Huangfu et al. (2003) identified 2 mouse mutants, wimple (wim) and flexo (fxo), that lack ventral neural cell types and show other phenotypes characteristic of defects in Sonic hedgehog (600725) signaling. Both mutations disrupt intraflagellar transport proteins: the wim mutation is an allele of the previously uncharacterized mouse homolog of Ift172, and fxo is a hypomorphic allele of polaris, the mouse homolog of Ift88 (600595). Genetic analysis showed that wim, polaris, and the intraflagellar transport motor protein Kif3a (604683) are required for hedgehog signaling at a step downstream of the hedgehog receptor Patched-1 (see 601309). Wimple embryos have an open anterior neural tube and lack a groove on the ventral midline of the anterior neural tube. In 5 of 8 wim embryos, nodal expression was observed bilaterally; the other 3 showed wildtype expression. Huangfu et al. (2003) concluded that intraflagellar transport machinery has an essential and vertebrate-specific role in hedgehog signal transduction. Halbritter et al. (2013) performed zebrafish knockdown of ift172 with 2 morpholino oligonucleotides and observed a similar phenotype with both: the morphants displayed ventral body-axis curvature, formation of kidney cysts, otolith defects, and hydrocephalus, a ... More on the omim web site

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June 30, 2020: Protein entry updated
Automatic update: OMIM entry 607386 was added.

Oct. 19, 2018: Additional information
Initial protein addition to the database. This entry was referenced in Bryk and co-workers. (2017).